Tracking loop for IR-UWB communications in IEEE 802.15 multi-path channels

In impulse-radio ultra-wide band (IR-UWB) communications, even a small timing error would lead to a serious degradation in system performance in the multi-path circumstance. To deal with the challenge, a novel hybrid synchronous sampling timing locked loop is proposed in this paper. Timing error detector, the crucial unit of TLL, is realized based on a maximum-likelihood estimation method. Both mathematical analysis and simulations on S-Curve and timing error variance indicate a high performance of the proposed TLL at low signal to noise rate. It is also demonstrated that in the environment of IEEE 802.15.3a Multi-path channels, the proposed TLL improves system bit error rate (BER) performance by two orders of magnitude when the timing jitters are around half a pulse duration. Furthermore, it is observed through simulations that five figures selective Rake receiver is advisable for a satisfactory system BER performance.